Liquid crystal display are classified according to the differences in the liquid crystal drive method (i.e. display mode) in the liquid crystal cell. One of these is the vertical alignment mode (hereinafter referred to as the “VA mode”) liquid crystal display, which is currently the main method utilized for large displays. Further, making liquid crystal displays even large requires a wider viewing angle, so it is preferable for mitigating the screen contrast drop and false colors that occur when a display is viewed from a slant.
For the optically anisotropic body used in the liquid crystal display, patent reference 1 proposes a phase difference film composed of a single layer organic aligned film having at least 1 maximum value and/or minimum value of phase difference value (i.e. frontal direction retardation) in wavelength range of 400 nm to 800 nm. Additionally, patent reference 2 proposes a VA mode liquid crystal display comprising a phase difference film wherein the frontal direction retardation and the thickness direction retardation satisfy a specific relationship at wavelengths of 450 nm and 550 nm. Using the phase difference film described in patent references 1 or 2 in a VA mode liquid crystal display slightly improves the contrast when viewing a display from a slant. There remains a great degree of screen false color, however, so these efforts are still unsatisfactory.
The configuration having a piece of optically anisotropic body such as phase difference film placed on each of both sides of the liquid crystal cell is widely used in a VA mode liquid crystal display. This is because the allowable range for the phase difference value such as the frontal direction retardation required of the optically anisotropic body is relatively wide. In addition, increasing the regular allowable range of the optically anisotropic body phase difference value increases the optically anisotropic body yield and improves the liquid crystal display productivity.
However, if simplifying the production process of liquid crystal displays is taken into consideration, reducing the number of optically anisotropic bodies, specifically using an arrangement that employs only one piece of optically anisotropic body on one side of the liquid crystal cell is preferable. Employing a configuration wherein only one piece of conventional optically anisotropic body as described in patent references 1 or 2 is placed on only one side of the liquid crystal cell, however, results in a narrow allowable range of the phase difference value required in the optically anisotropic body. This is not a problem if an optically anisotropic body with a phase difference value that fits within this narrow allowable range can be produced in large quantities, but the current production method for the long and wide optically anisotropic bodies used in large displays cannot easily place the phase difference value completely within the allowable range and the optically anisotropic body yield is low, which is an obstacle to improving liquid crystal display productivity.
[Patent Reference 1] Japanese Patent Laid-open No. 2003-177244
[Patent Reference 2] Japanese Patent Laid-open No. 2004-037837